AC contactor is used for long-distance connection or disconnection of a large amount of current load. Its main circuit breaker, because of arc extinguishing equipment, can connect or disconnect more than one hundred to several hundred amperes of current, which is generally used to operate the start and stop of three-phase electric asynchronous motor.

    The intermediate relay is usually used as the power circuit for data signal transmission, data signal protection, data signal enlargement and so on, except for the operation of small load (generally under 5a). For example, the output current of the triode output PLC is generally only more than 100 MAH. If it is used for the external load of the driver immediately, it will burn down the internal power circuit of the PLC

    At this time, the intermediate relay can be driven first, and then the electric shock accident of the intermediate relay can be used to operate the AC contactor, which has the function of data signal protection.

    The principle of AC contactor and intermediate relay is mostly the same. According to the power on of the solenoid coil, the circuit breaker is closed or broken to connect or disconnect the load.

    What's different is that the AC contactor is mainly used in the main power circuit to supply the load power system with large output power to the motor, heating pipe, etc. because the load power supply system is set, when the current of the power supply system is disconnected, it will cause electric arc. In order to avoid the electric and optical short circuit fault, the AC contactor is all arc extinguishing equipment.

    Most of the intermediate relays are used in the control circuit, for example, in the temperature controller of the automobile relay output, that is to say, the instrument panel drives the intermediate relay first, and the automobile relay drives the AC contactor or relay and other large loads.

    In terms of the total number of circuit breakers, the total number of circuit breakers of the intermediate relay is therefore more than that of the AC contactor. However, due to the different load of multiple belts, the main circuit breaker of the AC contactor is much larger than that of the intermediate relay, so the AC contactor is also much more expensive than the intermediate relay.

    In the natural environment of industrial production, most of the electromagnetic coils of AC contactors are of AC current, while the intermediate relays are of AC voltage.